Adenosine Analogues as Selective Inhibitors of Glyceraldehyde-3-phosphate Dehydrogenase of Trypanosomatidae via Structure-Based Drug Design

In our continuation of the structure-based design of anti-trypanosomatid drugs, parasite-selective adenosine analogues were identified as low micromolar inhibitors of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Crystal structures of Trypanosoma brucei, Trypanosoma cruzi, Leishmania mexicana, and human GAPDH’s provided details of how the adenosyl moiety of NAD+ interacts with the proteins, and this facilitated the understanding of the relative affinities of a series of adenosine analogues for the various GAPDH’s. From exploration of modifications of the naphthalenemethyl and benzamide substituents of a lead compound, N6-(1-naphthalenemethyl)-2′-deoxy-2′-(3-methoxybenzamido)adenosine (6e), N6-(substituted-naph-thalenemethyl)-2′-deoxy-2′-(substituted-benzamido)adenosine analogues were investigated. N6-(1-Naphthalenemethyl)-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (6m), N6-[1-(3-hydroxy-naphthalene)methyl]-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (7m), N6-[1-(3-methoxy-naphthalene)methyl]-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (9m), N6-(2-naphthalene-methyl)-2′-deoxy-2′-(3-methoxybenzamido)adenosine (11e), and N6-(2-naphthalenemethyl)-2′-deoxy-2′-(3,5-dimethoxybenzamido)adenosine (11m) demonstrated a 2- to 3-fold improvement over 6e and a 7100- to 25000-fold improvement over the adenosine template. IC50’s of thes